You cannot upgrade 5.6.6 to 6.7.6. According to the upgrade guide you have to upgrade your server to the latest 5.X version (5.6.7, download). Next you can finally upgrade to the latest 6.X version (at this moment 6.7.6 - the same as you tried).

Sorry, but not really. There shouldn’t be any database migrations from one point version to another, and the migrations are really the point of hitting the intermediate LTSs. Once upon a time, we accumulated database migrations indefinitely but with the 4.x LTS (IIRC) we started keeping only migrations since the previous LTS which is why you must hit each one in between. (Tell me if that’s not clear.)

which versions are you using (SonarQube, Scanner, Plugin, and any relevant extension)
Sonarqube 5.6.6

what are you trying to achieve
Planning to upgrade the Sonarqube version from 5.6.6 to 6.7.6

what have you tried so far to achieve this

We have tried to upgrade the sonarqube server but ran with the errors as mentioned in the ticket Link

We tried with several possibility to get the upgrade done successfully but with no luck
a. Increased the max open files count, ulimit, swappiness, mem in application for sonarapp user
sysctl -w vm.max_map_count=262144
sysctl -w fs.file-max=65536
ulimit -n 65536
ulimit -u 2048 as per the link
b. So SonarQube doc says MySQL is not recommended for large DBs… can you confirm
62775.9(DB size) - 51082.41(Project_measures size) is considerably so high for not able to manage?
c. We tried with this upgrade path: 5.6.6 -> 5.6.7 LTS -> 6.7.x LTS but no luck
d. We tried to cleanup the obsolete project more than 1 year and i dont see much difference post cleanup of project in database size
e. Currently we are having the count of 1166 active projects and LOC count of 22275656

Need your confirmation if the above is not feasible for Mysql community version and also plan to go with Oracle if it will work there in the DB

As per the pricing model, link which edition will be compatible for us to upgrade further.

Need point of contact to discuss further more details about proposal plan and architecture to be proposed for our environment.

I have uploaded the requested web.log from the server where it got failed. Kindly review and confirm for the same.

And also we wish to go for licensed edition if not working as expected and i would like to have conatct person details to discuss about architecture review and how to plan for implementation plan to get it implemented without any issues.